Apparatus for preventing the backfiring in internal combustion engines



Aug, 10, 1937.

s. G. HADJIDAKIS 2,089,364 APPARATUS FOR PREVENTING THE BACKFIRING IN INTERNAL COMBUSTION ENGINES Filed Aug. 9, 1935 2 Sheets-Sheet 1 F/gJ.

new FUEL .SUPPLy Aug. 10, 1937- s. G. HADJIDAKIS 2,089,364

APPARATUS FOR PREVENTING THE BACKFIRING IN INTERNAL COMBUSTION ENGINES Filed Aug. 9, 1935 2 Sheets-Sheet 2 Patented Aug. 10, 1937 PATENT OFFICE APPARATUS FOR PREVENTING THE BACK- FIRING IN INTERNAL COIVIBUSTION EN- GINES Stephan George Hadjidakis, Canes (Kreta), Greece Application August 9, 1933, Serial No. 684,356 In Greece August 12, 1932 19 Claims.

The invention relates to an apparatus for preventing backfiring in combustion engines, or for protecting the fuel supply or tank from the dangers of backfires. According to the invention this apparatus in its most essential part consists of a receptacle, partly filled with mercury, which is inserted either between the fuel tank and the carburetor or between the carburetor and the working cylinders of the engine. If desired a receptacle may be inserted in each of these locations. By this arrangement the fuel contained in the fuel tank or the mixture of air and fuel produced in the carburetor passes through the mercury filling, so that, in case of a backfiring the flame will not proceed farther than this mercury filling. I may also arrange a non-return valve in the pipe which dips into the mercury filling, which valve will be closed automatically by the mercury rising in the pipe as soon as an additional pressure is exerted in the mercury receptacle. Besides the inlet and the outlet pipes there is preferably provided a third pipe which also dips into the mercury and into which pipe electric contacts will be fitted and will be bridged 5 by the mercury rising in this pipe owing to the additional pressure, such contacts being connected to an electric circuit, controlling an alarm bell or an auxiliary motor or the like. In order to avoid an unduly high additional pressure in 30 the mercury receptacle it is also intended to provide a safety valve on the receptacle, which valve opens automatically when a predetermined pressure has been reached and which will permit a communication of the outer atmosphere with 35 the space above the mercury level in the receptacle.

When the apparatus is arranged between the carburetor and the working cylinder of the combustion engine and in order to avoid an unde- 40 sirable whirling up of the mercury filling, the

end of the pipe dipping into the mercury filling and which supplies the mixture of air and fuel, is preferably made in such a way that the mixture leaves the pipe through a large number of separate openings.

In order to avoid excessive cooling of the airfuel-mixture passing through the apparatus, I may provide a heating apparatus, for instance an electric coil, the heating action of which may be regulated by an electromagnetic regulator in connection with a contact thermometer.

The accompanying drawings show, as examples, some forms of the improved apparatus, and 55 in the drawings:

Fig. 1 is a longitudinal section through the apparatus.

Fig. 2 shows a modified form of construction of a part of the apparatus shown in Fig. 1.

The Figs. 3 to 7 inclusive show various forms of construction of the fuel feed pipe running into the mercury receptacle of the apparatus, when this apparatus is arranged between the carburetor and the working cylinder of a combustion engine.

Fig. 7a shows another form of construction of the entire apparatus in sectional view with the fuel feed pipe running between appropriate conically shaped partitions of the receptacle.

Fig. 8 represents an electro-magnetic regulator for the control of a heating device for the mercury receptacle.

Fig. 9 represents a contrivance which keeps the movable armature of the electro-magnetic regulator yieldingly in its different positions.

In Fig. 1 there is shown a receptacle I suitably made of metal, which may be of cylindrical form. The receptacle I is about half fi1ledor a little more than half filledwith mercury. On the one side the receptacle I is connected with a pipe 2 leading from the fuel tank of the combustion engine, and the open end of this pipe 2 dips to the length of some centimeters into the mercury in the receptacle. At a distance of a few centimeters above the level of the mercury in the pipe 2 there is provided a check valve 3 opening downwardly. The body of the valve 3 is conical, and is made of metal or any other material, the specific weight of which is lighter than that of the mercury. Through the provision of this valve 3 care has been taken that in case the mercury should rise in the tube 2, the fuel feed pipe will be closed automatically as soon as the level of the mercury reaches the valve.

A second tube 4 is connected to the receptacle I on the side which is opposite to the piping system 2 and extends into the space of the receptacle above the level of the mercury and, on the other hand, leads to the carburetor of the combustion engine. This tube 4 is provided with a metal lattice or a metal sieve 5, which permits passage of the fuel which must get to the carburetor, but which does not allow passage of the mercury.

Between the piping systems 2 and 4 a tube or pipe 6 is provided, this pipe 6 being preferably screwed into an opening of the receptacle l and in such a way that its open lower end dips as deep as possible into the mercury in the recepsoon as the mercury rises in the interior of the pipe and reaches the valve. Below the valve 8 two contacts 9 and I0 protrude from the inner side of the tube and are connected with two electric conductors II and I2 insulated in the interior of the pipe. These conductors are connected with a source of current, for instancethe electric battery of a motor car or an aeroplane, and

to this circuit an electro-magnetic switch has been inserted, the armature l5 of which serves to close or to interrupt the main circuit 56 which may be connected with an electric alarm bell or, an auxiliary motor. I

On the upper side of the receptacle I. there is mounted a bell-shaped flanged socket I! having openings 3 in the sides of its lower part and containing the piston I9.. By means of springs 20 this piston I9 is normally held so far down that the openings l8 in the sides are cut off. Consequently this contrivance acts as a safety valve and in case of a predetermined additional pressure in the receptacle l permits the escape of the gasinto the atmosphere or' into a pipe 2|, connected with the openings l8.

The supply of the liquid fuel from the fuel tank to the mercury receptacle I can be eficcted in-the usually known manner, either by gravity or by means of a feed-pump or finally through producing an additional pressure in the fuel tank. r

The fuel fed through the pipe 2 to the mercury receptacle lpenetrates into the mercury, and after leaving the pipe 2,. it rises in bubbles or drops to the surface of the mercury and into the space above the mercury. From this last mentioned space and by means of the pipe 4 the fuel passes to the carburetor, of the combustion engine. As experience has shown, the passage of the fuel through the mercury takes place with great smoothness and uniformity.

The above arrangement ensuresthatthe fuel contained in the fuel tank is separated by the mercury from the fuel contained in the receptacle i above the level of the mercury and in the pipe 4 connected with the receptacle. Now, if for any reason whatever a backfiring from the working cylinder of the combustion engine should occur, and the flame reach through the pipe 4 even into the space above the mercury level of thev receptacle l, the fuel contained in this space will be ignited and consequently an additional pressure will be created and will act on the surface of the mercury. The result will be that the mercury will rise into the tube 2 and as soon as it rises so far that it comes into touch with the valve cone of the check non-return valve 3, the said valve will be lifted and consequently closed, thus stopping completely the communication with the fuel tank.

But the mercury at the same time rises also into the pipe 6' and as soon as it comes here in touch with the contacts 9 and I0 and completes the electric circuit through the conductors ll and i2 and consequently also the-switch I4 and IE will be closed. The closing of theswitches M and i5 causes the alarm-bell connected. with the circuit Hi to sound and the chauffieur of the Elston-car or the pilot of the aeroplane will towards the top so that the openings l8 will be uncovered. and the gas may freely escape into the atmosphere or into the pipe 2!.

In the modified form of construction of the V pipe 6 as shown in Fig. 2, a bell-shaped member 22, suitably made of metal, has been provided for the top end, closing the pipe entirely on the top. In such a case a check-valve in the interior of the pipe is unnecessary. Otherwise the con struction of the pipe is the same as shown in Fig. 1.

The apparatus can also be installed between the carburetor and the working cylinder or cylinders of the combustion engine, instead of between the fuel tank and the carburetor of the combustion engine, .or if desired two such apparatus can be provided, one of them being placed between the fuel tank and the carburetor and receptacle l in liquid form, but as a mixture of gas and air. It appears that because of the great difference in the density of the mercury and that of the mixture of gas and air, a strong whirling up of the mercury would occur. In order to. avoid this undesirable occurrence, the end of thepipe 2 is dipping into the mercury and is constructed in such a way that the mixture of gas and air leaves the pipe through a large number of openings. This, for instance, can be obtained if the mouth of the pipe 2 contains one of the forms shown at Figs. 3-7.

In the construction illustrated in Fig. 3 the lower end of the pipe 2 is-connected with an undulated pipe 23' which extends along the receptacle 5 through the mercury and has a large number of openings 2%.

v Fig. 4 shows the pipe 2 leading into a cylindricallbodyfifi, which also has a large number of openings 2%. V

In the form of construction shown at Fig.5 the pipe 2 extends laterally into an about half cylindrical hollow body 25 which also possesses a large number of openings 26.

In the form of construction shown at Fig. 6 the pipe 2 has been connected with a device constructed as a rose 27 with shower openings 28 turned upwards.

The construction shown at Fig. '7 comp-rises a large number of small pipes 29 connected with the pipe 2 and extending radially outwards.

Through the construction of the mouth of the pipe 2 as described above carehas been taken that the mixture of air and gas passes through the mercury in the shape of small bubbles and enters the space of the receptacle above the mercury at a large number of different places. 7

In order to avoid in any case a whirling up of the mercury due to the passage of the mixture of gas and air a plate til, made of metal, for instance aluminium, may be provided, the plate Gil being perforated in order to allow the passage of the mixture and being placed on the surface of the mercury.

Y Care must be taken that the dipping depth of the feed pipe 2, or of the hollow body fitted to it, is such that the passage of the mixture of air and gas through the mercury is as easy as possible. The installation of the apparatus between the carburetor and the working cylinders of the combustion engine may have as a consequence a certain reduction of the speed of the flow of the mixture of oil and gas, but on the other hand there is the advantage that because of the passage of the mixture of air and gas through the mercury filling in small bubbles a better mixture of air and fuel will take place.

In the form of construction shown at Fig. 7a, the perforated device at the end of the fuel feed pipe 2 can be dispensed with and instead of this the inside of the receptacle I is supplied with convenient partition Walls 6|, conically arranged round the pipe 2, and which walls on the one hand will prevent the mercury from passing along with the fuel, which is obliged to take a zigzag course, on the other hand they will make it impossible for the mercury to flow out of the receptacle during a looping the loop.

These conical partition walls are arranged in such a way round the tube 2 that alternately some of same are secured on the tube 2 by means of arms 53 so that a ring shaped space between their top point and the tube 2 will be created through which the gaseous fuel will escape while the others are fixed directly to the tube 2 by means of their top point and thus will only allow the passage of the fuel under the lower edges of their conical surface.

In this case the end of the tube 2 can be fitted with a rotary pipe bend 64 which under the in fluence of gravity will follow each time the inclinations of the receptacle and consequently the end of the supply tube 2 will always be dipped entirely in the mercury filling.

This device is provided with a manometer 65 having a hand adapted to function in exactly .the same manner as the hand 3 I, Fig. 8.

The manometer 65 however is actuated by gas pressure and its needle or indicator is adapted to make and break contacts as in the case of the needle 32 of Fig. 8.

In order to avoid condensation of the gas and air mixture during its passage through the apparatus, the receptacle I may be provided with a heating apparatus, and specially for motor-cars and aeroplanes an electric heating apparatus should be provided, which, for instance, might be made of heating wires or heating coils (Fig. 8) surrounding the parts of the apparatus which should be heated. In order to prevent the heating temperature from passing beyond fixed maximum and minimum limits, it may be provided with an electric regulating device, which, for instance, can be of the type as shown in Fig. 8. In this Fig. 8 the wires or heating coils for the heating of the apparatus are represented by the coil 30. A metallic. thermometer 3| fitted in a convenient position on the apparatus regulates the flow of current to the heating coil 30, and has a hand which moves along a scale 33. On this scale 33 two adjustable contacts 34, can be regulated in accordance with the limits of temperatures which must be retained. The hand or needle 32 of the thermometer communicates with the positive pole of an electric battery or any other source of electric current 31, by means of the conductor 36, while the contacts 34 and 35 75 have been connected through the conductors 38 and 39 to the resilient contacts 40 and 4| respectively. The stationary contacts 40 and 4| cooperate with the contact bodies 42 and 43 respectively, these latter being firmly fixed around and movable with an armature 45, swinging about the axle 44. The armature 45 is placed between two electro-magnets 4'5 and 41, the coils of same on the one side being connected with the negative pole of the battery 31 through the conductors 48 and 49 and on the other side with the contact bodies 42 and 43 respectively of the armature 45. The armature 45 also carries the contact body 50 which communicates with the one end of the heating coil 30. Opposite to the contact body 59 a resilient contact 5| communicates with the positive pole of the battery 31.

In the manner shown at Fig. 9 a body 54 supplied with cuts or notches 52 and 53 may be suitably arranged below the free end of the armature 45, this body 54 being pressed against the armature 45 by means of springs 55, thus keeping same resiliently in place in either of its extreme positions.

Consequently the regulating device will operate as follows:

When the armature 45 is in its right hand extreme position, and consequently catches the notch 53 of the body 54, the contact 4!], 42 is closed, while the contacts 4|, 43 and 55, 5| are open. Consequently the heating coil 30 is cut off. If now the temperature of the device to be heated and indicated by the thermometer 3| has gone so far down that the needle 32 tuming in a counter-clockwise direction, comes in contact with the contact 34, the circuit of the left-hand magnet 46 will be closed and the armature consequently will be drawn from its right hand into its left hand extreme position Where its free end will catch in the notch 52 of the body 54. The result will be that the contact 40, 42 will be interrupted and the contacts 4|, 42 and 50, 5| will be closed. Through the closing of the contacts 50, 5| the heating coil 30 will be switched on so that it will transmit heat to the device which must be heated. In accordance with the rise of the temperature the needle 32 of the thermometer 3| will turn in a clockwise direction. As soon as the temperature has risen so far that the needle 32 comes in touch with the contact 35, the circuit of the right hand electro-magnet will be closed as the contacts 4| and 43 contact between themselves and as a consequence hereof the armature 45 once more will be moved to the right hand extreme position while the heating coil 36 will be interrupted.

Consequently care will be taken in a simple and reliable manner through means of this regulation device that the heating temperature always stays within certain limits which may be determined through the regulation of the contacts 34, 35 as desired.

The contacts 43, 4| and 5| may be made elastic in such a way that the interruption of the circuits belonging to them will occur only when the armature 45 has been moved from the one extreme position to the other. Contact brushes suitably arranged on the contacts 34, 35 or the needle 3| itself will effect the contact in order to avoid any impediment of the needle 32 on the scale 33. It is of course well understood that the contact bodies 42, 43 and 5B fitted on the armature must be well insulated between themselves.

The receptacle is suspended or supported in any suitable manner and its pipe connections 2 and 4 maybe made of rubber or other flexible:

material.

In its details this invention of course is not limited to the forms of construction as shown, on the contrary in accordance with each special case in hand and its needs various constructional modifications can be made accordingly. So for instance and in case that no importance is given to the working of an alarm-bell or an auxiliary motor working under the influence of the additional pressure in the mercury receptacle I, the installation of the pipe 5" can be entirely left out.

Consequently I do not limit myself strictly to the details herein-illustrated, since manifestly the same can be considerably varied without departing from the spirit of the invention as defined in the appended claims.

What I claim is:

1. A safety apparatus for the protection of the fuel in the fuel container from the danger of back-fires in combustion engines, comprising a receptacle, mercury in said receptacle forming a mercury seal permitting passage of fuel from the container to the engine and preventing the passage of a flame from the engine to the said container and a check valve actuated by the mercury for preventing passage of the mercury to the fuel container.

2. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle, mercury in the receptacle, a conduit communicating with the fuel-supply and opening into the receptacle beneath the level of the mercury, a check-valve preventing passage of the. mercury through said conduit and a conduit leading from the space above the mercury in the receptacle to the engine, the mercury preventing the passage of a flame from the latter to the former conduit.

3. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle interposed betwe-en the fuel-supply and the carburetor of the engine, a conduit admitting liquid fuel from the fuel-supply to the lower part of said receptacle, a conduit supplying liquid fuel from the receptacle, a body of mercury carried in the receptacle and preventing the admission of flame from the receptacle to the first-mentioned conduit and a check-valve preventing the passage of the mercury through said conduit.

l. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle interposed between the. carburetor and the admission valve of the engine, a body of mercury in the receptacle, a conduit conveying a combustion mixture from the carburetor to the receptacle beneath the level of the mercury, a check-valve for preventing the passage of mercury through said conduit, and a conduit for conveying the combustion mixture from the upper part of the receptacle to the admission valve of the engine.

5. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a mercury containing receptacle for connection between the carburetor of the engine and the intake valves thereof, a conduit for supplying the mixture and extending into the receptacle, and dipping beneath the level of the mercury therein, a conduit leading from the upper part of the receptacle above th level of the mercury for supplying the mixture to the inlet valves of the engine, and means for distributing in the body of mercury the combustible mixture through the first-mentioned conduit.

6. A safety apparatus for the protection of the fuel supply from the danger of back-fires in com bustion engines, comprising a mercury containing receptacle, a fuel connection from the supply to the receptacle, a check-valve, for preventing the admission of mercury into said connection, and a connection for the passage of fuel from the receptacle to the engine.

7. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle, a body of mercury partly filling the receptacle, a fuel conduit leading from the fuel-supply and dipping into the mercury in the receptacle, a multiplicity of holes in the conduit for the emission of the fuel beneath the level of the mercury, and a conduit forleading the fuel, from above the mercury level in the receptacle, to the engine.

8. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle, mercury partly filling the receptacle, a pipe extending downwardly into the mercury in the receptacle and supplying a combustible mixture thereto, a hollow member submerged in the mercury and receiving the mixture from said conduit, a large number of holes in said hollow member for distributing the mixture throughout the mercury, and a conduit leadingto the engine from the space in said receptacle above the level of the mercury for the conveyance of combustible mixture.

9. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprisinga receptacle, mercury partly filling the receptacle, means for the conveyance of liquid fuel to the receptacle beneath the level of the mercury, means for preventing the passage of mercury from the receptacle through said fuel conveyance means, and means for conveying liquid fuel from the space above the mercury to the engine.

10. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle for connection between the fuel supply and the engine, a body of mercury partly filling the receptacle, a conduit admitting fuel to the receptacle beneath the level of the mercury, a conduit for the passage of I fuel from above the mercury level in the receptacle, an electric switch controlled by contact with the mercury on movement of the mercury level due to excess pressure within the receptacle, an electric circuit controlled by said switch and a signal device actuated by the circuit.

11. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle, a body of mercury partly filling the receptacle, means for admitting fuel to the receptacle beneath thelevel of the mercury, means 'for conducting fuel from above the mercury level in the receptacle to the engine, a spring-loaded release valve in the receptacle, and a mercury-actuated check-valve for preventing the passage of the mercury through the fuel-supply means.

12. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle, mercury partly filling the receptacle, a pipe opening into the receptacle beneath the level of the mercury, a second pipe opening into the receptacle above the level of the mercury, a mercuryactuated check-valve in the former pipe, and a mercury-contact electric switch for stopping the operation of the engine and preventing flow through said pipes when the pressure within the receptacle exceeds a predetermined limit. 13. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle, mercury partly filling the receptacle, a pipe admitting combustible mixture tothe receptacle beneath the mercury level, a pipe conveying combustible mixture from the space above the mercury to the engine, and means for automatically maintaining between predetermined limits the temperature of the receptacle to ensure against condensation of the mixture.

14. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle,

mercury partly filling the receptacle, a fuel supply pipe extending downwardly into the receptacle, a pipe for the passage of fuel from the upper part of the receptacle to the engine, a mercury actuated check-valve in the said first-mentioned pipe a third pipe extending downwardly into the mercury, a screen in the upper end of said pipe, a mercury-actuated check-valve in said pipe, and a mercury switch actuated by movement of the mercury due to increase in pressure in the receptacle to stop the engine.

15. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle, mercury partly filling the receptacle, a pipe opening beneath the level of the mercury in the receptacle and leading combustible mixture to the receptacle, means on said pipe for distributing the mixture throughout the mercury, a member on the surface of the mercury for ensuring the distribution of the mixture from said pipe, a pipe for conveying combustible mixture from above the level of the mercury in the receptacle to the engine, a pressure-release valve in the receptacle,

5 and at least one automatic check valve for retaining the mercury in the receptacle.

16. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle,

50 mercury partly filling the receptacle, a pipe supplying combustible mixture to the receptacle beneath the level of the mercury, a second pipe conveying combustible mixture from the receptacle to the engine, a third pipe extending downwardly into the mercury, a screen on the upper part of the latter pipe, a mercury-actuated check valve in each of the two pipes extending into the mercury, an electrical switch actuated by contact with the mercury due to excess pressure in the receptacle, a signal-actuating circuit controlled by said switch, and an excess pressure release Valve on the receptacle.

17. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle, mercury partly filling the receptacle, a pipe supplying combustible mixture to the receptacle beneath the level of the mercury, an automatic check-valve in said pipe, a pipe conveying combustible mixture from above the surface of the mercury to the engine, a tube extending through the top of the receptacle downwardly into the mercury, a screen in the upper part of said tube, an automatic check-valve in said tube, and electrical contacts extending into said tube for engagement by the mercury due to excess pressure within the receptacle, and an electrical signal control circuit connected to said switch.

18. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle between the fuel supply and the engine, a body of mercury partly filling the receptacle, a conduit extending downwardly into the mercury and admitting fuel to the receptacle beneath the level of the mercury, a rotary pipe forming a fuel outlet on the end of said conduit, said pipe being free to swing by gravity to maintain its outlet end always submerged in the mercury, and a conduit for the passage of the fuel to the engine from above the mercury level in the receptacle.

19. A safety apparatus for the protection of the fuel supply from the danger of back-fires in combustion engines, comprising a receptacle between the fuel supply and the engine, a body of mercury partly filling the receptacle, a conduit extending downwardly into the mercury and admitting fuel to the receptacle beneath the level of the mercury, a group of conical partitions encircling said conduit and providing a zig-zag course for the fuel, a rotary pipe forming a fuel outlet on the end of said conduit, said pipe being free to swing by gravity to maintain its outlet end always submerged in the mercury, and a conduit for the passage of the fuel to the engine from above the mercury level in the receptacle.

STEPHAN GEORGE HADJIDAKIS. 

